Artificial silk and method of producing same



Patented July 23, 1935 PATENT OFFICE ARTIFICIAL SILK AND METHODOF PRODUCING SAME William L. Hyden, Kenmore, and John S. Fonda, Buffalo, N. Y., assignors to Du Pont Rayon Company, New York, N. Y., a corporation of Delaware a No Drawing. Application February 12, 1930,

Serial No. 427,936

24 Claims.

This invention relates to the manufacture of artificial silk. More particularly, it relates to artificial silk having a subdued luster or sheen simulating natural silk and to the process of preparing the same.

Artificial silk produced by the usual methods possesses a high luster and brilliance. Originally, this characteristic was the reason for its reception and extensive use. Experience has shown that for certain purposes and in many instances the high luster is, in fact, a limitation and that a soft, low luster similar to or even lower than that of natural silk is very much desired.

1 Prior to this invention, various methods have been devised to produce artificial silk having the desired degree of luster. Some of the methods contemplated the deposition on the fibers of a material which produced a mat effect. One of such methods comprised treating the finished thread, preferably in the form of skeins, with a solution of a water-soluble salt of barium, such as barium chloride, followed by a treatment with a solution containing sulphuric acid or a sulphate. The barium sulphate, formed by the reaction of the two solutions, was precipitated upon the fibers and imparted to them an appearance of low luster. Another method contemplated the immersion of skeins of thread in a solution containing metallic salts, such as titanium sulphate,

and subsequently converting said titanium salt to a water-insoluble titanium compound, such as titanium oxide. Both of these methods possessed many disadvantages. To produce the desired result required such a large quantity of material that the thread was adversely affected. Furthermore, both procedures resulted in products having the luster-reducing material disposed on the surface thereof. The precipitated compound was not permanently secured to the thread.

Thus, when fabrics containing these threads were subjected to washing or friction, the luster of various areas thereof was wholly or partially restored. In addition, the luster did not approxi- 45 mate that possessed by natural silk.

Other methods contemplated the introduction of various non-opaque materials having difi'erent indices of refraction from the material of which the thread was formed or opaque substances to a 50 spinning solution and spinning the resulting composition.

Those methods which depended on-light refraction and reflection, that is, on the introduction of such materials as mineral oils, etc,

55 though they produced artificial thread having substantially permanent low luster eflects, seriously aflected the physical properties of the product. The tensile strength of the resulting product was lower than that of a thread similarly produced without the use of the above-mentioned 5 constituents. In many cases the loss in strength was so marked that it made the process impractical. 'Moreover, the luster was not similar to the peculiar appearance of natural silk.

The process of producing a thread having a 10 low luster by the use of an opaque body involved the spinning of a solution containing an opaque body, such as a pigment, suspended therein. The luster produced was a function of the amount and nature of the pigment employed. 15 Unless a relatively large quantity of pigment were used, a rather harsh metallic luster was obtained which made the yarn opaque but still left it highly and objectionably lustrous. When large quantities of pigments are employed in order toprevent the objectionable sheen, the yarn becomes weak, harsh and even brittle. In addition to not possessing the sheen so characteristic of natural silk, the dyeing characteristics of the thread maybe so seriously aflected that special dyes or special dyeing procedure may be required to give full, even and uniform shades.

We have found that we can produce an artificial silk having the desired type of luster and overcome the above-mentioned defects by in- 30 troducing into the spinning solution a non-opaque material, such as a liquid, which has an index of refraction different from the material of which the thread is constituted and thus reflects light, in combination with an opaque material. Due to the lack of a proper term to generically designate the liquid materials used in the instant invention, the term liquid is herein used to cover animal, vegetable or mineral oils and any non-opaque liquids which are non-volatile, in- 40 compatible with the freshly spun or final filament or both and have indices of refraction different from the material of which the finished thread is composed. This terminology is not intended to cover those materials which are used j as distributing agents or stabilizers since, for theuniform distribution of the low luster inducing materials in the prior art methods, as well i as in the instant invention, the proportions of distributing agents usually used produce practically no lowering of the luster.

It is therefore an object of this invention to produce artificial silk having a luster equal to or lower than that possessed by natural silk.

Another object of this invention is to provide a 5 method of producing artificial silk having a luster closely simulating or lower than that of natural silk.

A specific object of this invention is to providea method of producing artificial silk of a low luster which comprises spinning a composition containing a non-opaque liquid having an index of refraction different from the material constituting the thread conjointly with opaque particles, both of which will impart opacity to the finished thread, whereby the luster of the product is similar to or lower than natural silk.

Other objects will appear from the following description and appended claims.

According to this invention, opaque particles capable of rendering the resulting thread opaque in combination with a liquid of the type above described are added directly to the spinning solution or at some stage in the preparation thereof and the resultant composition spun in the wellknown manner. It is apparent that any of a large number of opaque substances may be employed in this process. Successful results are secured by using pigments including carbon black, titanium oxide, zinc oxide, lithopone, blanc fixe, and zinc sulphide. Likewise, any of a large number of liquids including white oil, linseed oil, white rose oil, castor oil, cottonseed oil, cocoanut oil and neatsfoot oil, may be employed with success. Various proportions of these substances may be employed depending upon the degree of luster desired. Satisfactory results are secured by using a composition including a viscose solution containing approximately 7% cellulose and the ingredients in the following proportions:

Pigments 0.0005%-0.50% Liquids 0.05 %2.00

In order to more clearly illustrate the invention, several examples are hereinafter set forth. In these examples the quantities given are by weight and are based on the weight of the viscose which contains approximately 7% cellulose, although it is within the purview of this invention to vary this percentage of cellulose.

Per cent 1. Carbon black 0.0005 White oil 0.25

2. Titanium oxide l 0.02 White oil 0.20

3. Titanium oxide 0.075

Boiled linseed oil 0.10

4. Zinc oxide 0.10 Boiled linseed oil 0.06

5. Lithopone 0.04 White oil 0.30

6. Blanc fixe 0.10 White oil 0.30

'7. Zinc sulphide 0.02 White rose oil 0.30

8. Zinc sulphide 0.01 White oil 0.80

The spinning composition may be compounded in numerous ways. The manner immediately following illustrates one mode of procedure.

A suspension of the pigment is made by slowly adding 9.08 grams of finely divided zinc sulphide pigment with constant stirring to 400 cc. of a 1% aqueous sodium oleate solution. To this suspension is gradually added and with constant stirring 136 grams of white rose oil. After the dispersion is completed, the final product is added to pounds of viscose containing 7% cellulose with constant stirring until a uniform composition is obtained. This composition is then ripened and spun in the usual manner.

Although it is not essential, we prefer to suspend the pigment in a previously or separately prepared emulsion of the liquid in water before adding the combination to the viscose. It is understood that the pigment may be added to the emulsion as a suspension in water or in the liquid. Any suitable emulsifying or stabilizing agent, such as soaps, sulphonated vegetable oils, alkyl naphthalene sulphonic acid salts and the like, may be used in the preparation of the emulsion. The nature of the emulsifying agent is immaterial so long as it produces satisfactory emulsion and does not interfere with spinning.

It is to be understood that the liquid and pigment may be added at other points in the process as, for instance, to the steeping caustic, to the alkali cellulose before xanthation or to the carbon di-sulphide.

Though the method hereinabove described refers specifically to viscose, it is to be understood that the invention is not restricted thereto since it is obvious that it may be used with any type of spinning solution including cuprammonium cellulose, cellulose nitrate, cellulose acetate and other cellulose derivatives by proper choice of low luster inducing liquids.

The artificial silk produced from the foregoing process constituting a part of this invention has a type of luster not hitherto attained in artificial silk. It is low and soft and may be so regulated as to resemble natural silk depending on the quantities of both of the materials incorporated in the mass of the thread. By reason of its method of manufacture, the luster is substantially permanent. Moreover, the thread possesses an improved tensile strength over that which can be secured by the use of liquids alone and an improved capacity for dyeing over that which can be secured by the use of pigments alone. The thread produced by applicants process is solid, that is, it is different from so-called hollow filament yarns which may be produced by the introduction of volatile liquids in the spinning solution. These hollow filament yarns are characterized by highly crenelated or deeply channeled surfaces and they may also contain particles of air enclosed within the filament. Applicants thread contains no such air particles within the thread, nor is the surface of the thread any more crenelated or channeled than an ordinary rayon thread.

Since it is obvious that various changes and modifications in the specific details described may be made by one skilled in the art without departing from the nature or spirit of the invention, this invention is not restricted thereto except as set forth in the appended claims.

We claim:

1. Artificial silk of the solid variety having a low luster and containing an opaque substance and a finely divided non-opaque substance having a different index of refraction from the material of which the silk is composed substantially homogeneously and uniformly incorporated and distributed throughout its mass, the opaque and nonopaque substances each being present in such a quantity that each contributes to the low luster.

2. Artificial silk of the solid variety having a low luster and containing a pigment and a non-volatile low luster-inducing liquid substantially. homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and liquid each being present in such a quantity that each contributes to the low luster.

3. Artificial silk .of the solid variety having a low luster and containing a pigment and a non-volatile organic low luster-inducing liquid substantially homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and organic liquid each being present in such a quantity that each contributes to the low luster.

4. Artificial silk of the solid variety having a low luster and containing a pigment and a low luster-inducing oil substantially homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and oil each being present in'such a quantitythat each contributes to the low luster.

5. Artificial silk of the solid variety having a low luster and containing titanium oxide and white oil substantially homogeneously and uniformly incorporated and. distributed throughout its mass, the titanium oxide and white 011 each being present in such a quantity that each contributes to the low luster.

6. Artificial silk having a low luster and containing 0.0005% to 0.50% of a pigment and 0.05% to 2.00% of a non-volatile low luster-inducing liquid substantially homogeneously and uniformly incorporated and distributed throughout its mass.

'7. Regenerated cellulose structures including solid artificial silk having a low luster and containing an opaque substance and a finely divided non-opaque substance having a difierent index of refraction from the material of which the silk is composed substantially homogeneously and uniformly incorporated and distributed throughout its mass, the opaque and non-opaque substances each being present in such a quantity that it contributes to the low luster.

8. Regenerated cellulose structures including solid artificial silk having a low luster and containing a pigment and a non-volatile low lusterinducing liquid substantially homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and liquid each being present in such a quantity that each contributes to the low luster.

9. Regenerated cellulose structures including solid artificial silk having a low luster and containing a pigment and a non-volatile low lusterinducing organic liquid substantially homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and liquid each being present in sucha quantity that each contributes to the low luster.

10. Regenerated cellulose structures including solid artificial silk having a low luster and containing a pigment and a low luster-inducing oil substantially and homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and oil each being present in such a quantity that each contributes to the low luster.

11. Regenerated cellulose structures including solid artificial silk having a low luster and containing titanium oxide and white oil substantially homogeneously and uniformly incorporated and distributed throughout its mass, the titanium oxide and white oil each being present in such a quantity that each contributes to the low luster.

12. Regenerated cellulose structures including solid artificial silkhaving a low luster and containing 0.0005% to 0.50% of a pigment and 0.05% to 2.00% of a non-volatile low luster-inducing liquid substantially homogeneously. and uniformly incorporated and distributed throughout its mass.

13. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in dispersing both a pigment and a non-volatile low luster-inducing liquid in a viscose solution, and extruding the resultant solution in the well known way.

14. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in dispersing both a pigment and a low lusterinducing oil in a viscose solution, the pigment and oil each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant solution in the well known way.

15. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in dispersing both titanium oxide and white oil in a viscose solution, the titanium oxide and white oil each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant solution in the well known way.

16. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in forming a dispersion of a pigment and a nonvolatile low luster-inducing liquid, homogeneously dispersing said dispersion in a viscose solution, the pigment and liquid each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant composition in the well known way.

1'7. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in dispersing both a pigment and a non-volatile low luster-inducing liquid in a viscose solution at some stage in the preparation thereof, the pigment and liquid each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant composition in the well known way.

18. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in forming a dispersion of a pigment and a nonvolatile low luster-inducing liquid, dispersing said dispersion in a viscose solution at some stage in the preparation thereof, the pigment and liquid each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant composition in the well known way.-

19. A method of producing regenerated cellu- I known way.

20. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which consists in emulsifying a non-volatile low luster-inducing liquid in water, suspending a pigment in the emulsion, dispersing the thus formed dispersion in a viscose solution at some stage in the preparation thereof, the pigment and liquid each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant composition in the well known way.

21. A method of producing regenerated cellulose structures including artificial silk of the solid variety having a low luster which comprises emulsifying a low luster-inducing oil in water, suspending a pigment in the emulsion, dispersing the thus formed dispersion in a viscose solution prior to the extrusion thereof, the pigment and oil each 'being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant solution in the well known way.

22. A method of producing regenerated cellulose structures including solid artificial silk having a low luster which consists in emulsifying white oil in water, suspending titanium oxide in the emulsion, dispersing the thus formed dispersion in a viscose solution prior to extrusion, the titanium oxide and white oil each being present in such a quantity that each contributes to the low luster of the product, and extruding the resultant composition in the well known way.

23. Artificial silk of the solid variety having a low luster and containing an inorganic pigment and a non-volatile low luster-inducing organic substance substantially homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and substance each being present in such a quantity that it contributes to the low luster.

24. Regenerated cellulose structures including solid artificial silk having a low luster and containing an inorganic pigment and a non-volatile low luster-inducing organic substance substantially homogeneously and uniformly incorporated and distributed throughout its mass, the pigment and substance each being present in such a quantity that it contributes to the low luster.

WILLIAM L. HYDEN. JOHN s. VFONDA. 

